Abstract:The magnitude of tropical cooling during the Last Glacial Maximum (LGM) has been the subject of uncertainty for over 25 years. We use principles of meta-analysis as an objective approach to reconcile estimates from different proxies. This approach treats each observation as a random estimate of the true mean and weights estimates by their reported precision. We assigned global uncertainties to proxies and derived a new regional standard deviation for temperatures calculated from the Sr/Ca ratio in tropical corals (σ = 1.4°C). Using a Bayesian spatial interpolation scheme, we estimate a mean cooling of LGM tropical sea surface temperatures of -2.7 ± 0.5°C (±σ) and surface air temperatures of -5.4 ± 0.3°C (±σ). Copyright 2005 by the American Geophysical Union.